Changes in the ultrastructure and functions of immunocompetent cells under the influence of external heating, interleukin 1 beta and leukocytic pyrogen.

The structural and functional organization of the rabbit immunocompetent cells after injection of human recombinant interleukin 1 beta (IL-1 beta), partially purified leukocytic pyrogen (LP), or after external heating (36 degrees C, 1.5 h) was compared. A rectal temperature increase being the same, there were similar and transient changes in epithelial and endothelial cells and macrophages, a rise in the proliferative activity of thymocytes and synthesis of IL-1-like activity, and a decrease in the interleukin 2 (IL-2) production by cultured splenic cells.